To provide an air conditioner for an electric vehicle preventing application of excessive current, or occurrence of a start impossible state and vibration of an electric motor for a compressor regardless of a magnitude of a load of the compressor, to easily start the motor.

In this air conditioner, a start load applied to the compressor 2 is estimated in consideration of environmental temperature and pressure detected by a pressure sensor 15 detecting gas refrigerant pressure on the high pressure side of the compressor 2. By selecting a forcible drive time of the motor 3 for the compressor 2, a time required for increasing a rotational speed and drive voltage according to the estimation result of the start load and executing a start process, the application of the excessive current, the vibration and the generation of the start impossible state are prevented to easily start the motor 3 for the compressor 2.